The present invention relates generally to passive vehicle safety belt systems and, more particularly, to systems for inhibiting lock-up of an inertially operated passive safety belt system take-up spool when, during non-emergency conditions, the vehicle door is open.
In the copending application of William M. Hollowell and Avraham Ziv entitled "VEHICLE SENSING INERTIA REEL LOCKUP INHIBITOR", Ser. No. 872,306, filed Jan. 25, 1978, and assigned to the common assignee of this application, an in-depth discussion is made of various vehicular safety belt systems and one technique for inhibiting, but not preventing, lock-up during the opening of the vehicle door of an inertially operated safety belt retractor of the type mounted within the door of the vehicle to provide upper torso restraint. According to the teaching of said application, an external biasing force is applied to the high inertia mass contained within the retractor activation mechanism during the door opening operation in order to make the high inertia mass more resistive to moving from the unlocked to the locked position during door opening operations. Several embodiments for accomplishing this are shown therein. A separate sensor (mechanical or electrical) is employed according to the teaching of said application to apply and remove the biasing force to the high inertia mass.
In the copending application of Albert R. Close entitled "AUTOMATIC RETRACTOR INHIBITOR," Ser. No. 878,730, filed Feb. 17, 1978, and assigned to the common assignee of this application, further improved variations are shown for providing a simpler, less costly, and/or faster operating retractor inhibiting mechanism. According to the teaching of said application, a second fulcrum point is selectively engaged whenever the door is open to impose a longer moment arm upon the pendular high inertia mass to increase the magnitude of force, in the direction associated with opening the door, necessary to cause the pawl to engage the spool causing lock-up. A second variation of inhibiting means disclosed by said application includes the selective engagement of a second fulcrum point with a tippable high inertia mass whenever the door is open, to inhibit tipping of said mass in the direction associated with opening of the door to, again, inhibit motion of the pawl into locking engagement with the spool during non-emergency conditions.
While the various apparatus disclosed in said copending applications work well for their intended purposes in many applications, there are some instances where lock-up in a fail-safe manner is highly desirable.